The present invention relates to a color television (TV) signal playback apparatus which plays back a color TV signal out of a magnetic tape by a magnetic head while readily compensating the phase of a reproduced color signal and the period of a horizontal sync signal.
When a color TV signal is recorded into a magnetic tape, horizontal sync signals in adjacent tracks are sometimes misaligned with each other. Should such a magnetic tape be transported to play back at a speed different from a recording speed (variable speed playback) or in the opposite direction to a recording direction for presenting backward picture motion, the TV signal picked up by the head might have a horizontal sync signal period deviating from the normal value, i.e. 1 H (one horizontal sync). The deviation has to be compensated for during playback in order to attain the normal period. Such compensation will hereinafter be referred to as "horizontal sync signal period compensation" or "H-period compensation".
Concerning a color TV signal in accordance with the phase-alternation line (PAL) system, when it is played back after being recorded in the above-described condition, the reproduced picture will lose colors because the phase of the color burst signal in the color TV signal fails to match with a phase prescribed by the standards. Therefore, during playback, it is necessary to compensate color signal phases such that the color burst phases are in a predetermined order. This compensation will hereinafter be called the "color sequence compensation" for convenience.
Some color TV signal playback apparatuses are known in the art which feature the above-described H-period compensation and color sequence compensation capabilities. However, because all the prior art apparatuses of the kind concerned are designed to demultiplex a luminance signal and a color signal after H-period compensation, subject the color signal to color sequence compensation, and then multiplex the color and luminance signals again, various circuit elements such as a burst gate pulse generator, a multiplexer, a burst phase detector, a VXO and a demultiplexer are required in addition to a circuit usually installed in a magnetic recording and playback apparatus for producing a burst phase detection output. Therefore, the entire circuit construction is intricate and bulky.